Estudo das propriedades magnéticas e hiperfinas de compostos NdFe2-xCrxSi2

• Autor(a) principal: Veiga, Mislayne Oliveira da
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/2688
• topic: Compostos intermetálicos, Pseudoternários, Magnetização; Difração de raios; Mössbauer, Difração de raios X; Brasil.; Intermetallic compounds; Pseudo-ternaries; Mössbauer; Magnetization; X-Ray diffraction; Brazil.; Ciências Exatas e da Terra; Física

Intermetallic compounds NdFe2-xCrxSi2-type, with 0 ≤ x ≤ 1.75, were prepared by arc melting and subsequent heat treatment. The samples were characterized by X-ray diffraction, magnetization and Mössbauer spectroscopy techniques, including measurements at low temperatures for the last two techniques. The results showed single-phase samples, or secondary phases in trace amounts, and antiferromagnetic correlations in the paramagnetic state. For x = 0 and x = 0.75, magnetic transitions to the AFM order or to a spin glass state, respectively, have been identified. Other samples showed no transitions to the lowest measured temperature (10 K). With the exception of the compound showing spin glass and strong coercivity behavior at low temperatures, all other revealed metamagnetic or spin flop behavior under the application of intense magnetic fields. The Mössbauer spectra revealed very low hyperfine magnetic fields throughout the temperature range of measurement, which were attributed to the conduction electrons around the iron atoms, polarized by RKKY interaction generated by moments of neodymium atoms.